1. Field of the Invention
The present invention relates to recording heads and other types of heads used for recording apparatuses, and more particularly, to a recording head having a function for identifying the recording head, a recording apparatus having the recording head, a method for identifying the recording head, and a method for giving identification information to the recording head.
2. Description of the Related Art
The present invention can be applied to apparatuses such as a printer, a copying machine, a facsimile machine having a communication system, and a word processor having a printer all of which perform recording onto recording media, such as paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, and ceramics. The present invention can also be applied to industrial recording apparatuses complexly combined with various processing apparatuses.
xe2x80x9cRecordingxe2x80x9d in the present invention means not only giving a meaningful image such as a character or a figure to a recording medium, but also giving a meaningless image such as a pattern to a recording medium.
Conventional recording apparatuses are configured such that various recording heads and scanner heads can be replaceably mounted, to respond to various demands. As an example of such an apparatus, by preparing a scanner unit for optically reading the original in substantially the same shape as a recording head and using it instead of a printing head, a recording apparatus is used not only for recording but for reading the original. A recording apparatus can also be used for recording with different image quality by mounting another head having a different type of ink.
In another example, to compensate for dispersion in manufacturing recording heads, the best driving condition of a recording head is stored in the recording head when it is manufactured, and a recording apparatus automatically reads and identifies this driving condition to automatically set it.
In yet another example, to reduce cost by using common components in the heads corresponding to a plurality of recording apparatuses, the heads are manufactured in similar shapes. In this case, it is necessary to identify each head so as not to mount an erroneous head to each recording apparatus.
To respond to various demands such as those described above, it is demanded that a recording head be provided with means for identifying more types of recording heads.
Various methods have been used to satisfy such a demand. In a first method, a plurality of identification terminals are provided as terminals for electrically connecting a recording apparatus to a recording head, each of these terminals is grounded or connected to a power supply according to the type of the corresponding recording heads, and the recording head is identified by a low-level signal or a high-level signal. In this method, recording heads of the n-th power of 2 can be identified by providing xe2x80x9cnxe2x80x9d terminals.
In this method, however, many contacts are needed to identify many recording heads. This not only increases the cost of a recording head and a printing apparatus, but also reduces reliability as the number of contacts increases.
In a second method, electrically multi-level conditions are used in order to identify a plurality of states at one contact. In the simplest method, a resistor is provided for a recording head and the resistance thereof is read by a recording apparatus to identify the head.
In this method, although an identification resistor needs to be provided for a recording head, since it cannot be implemented just by the pattern of a contact, the cost increases. In addition, with dispersion of the contact resistance of a contact being taken into account, it is impossible to largely increase the types of recording heads which can be identified. Furthermore, a recording apparatus needs to have not only just a logic circuit but also an expensive circuit such as an A-D converter.
A third method uses serial data transfer. In this method, a circuit which implements serial transfer is provided for a head. A memory area for identification data is kept in the head and the data is transferred to the recording apparatus.
With this method, since any large amount of identification information can be transferred just by providing three terminals, one for the start pulse of serial transfer, a clock terminal, and a data terminal, in addition to usually required terminals, such as the ground terminal and the power-supply terminal, a number of heads can be identified with this number of terminals. However, because these three terminals are positively required and a serial transfer circuit for identification information is also needed inside the apparatus, the cost thereof increases.
In any of the above methods, a number of terminals are required to give a large amount of identification information to the head, the cost increases, or reliability is not assured.
Accordingly, it is an object of the present invention to provide a head having a low-cost, highly reliable identification method in which a number of identification terminals are not required and one identification terminal indicates a number of states, an apparatus having the head, the head identification method, and a method for giving identification information to the head.
Another object is to provide a head having many types of identification information, which can be easily mass-produced.
One of the foregoing objects is achieved in one aspect of the present invention through the provision of a head detachably mounted on an apparatus and driven, including: a driving signal line having a driving terminal for receiving a driving signal of the head from the apparatus; and a head identification terminal, wherein the driving signal line is electrically connected to the head identification terminal.
One of the foregoing objects is achieved in another aspect of the present invention through the provision of a recording head for recording with the use of a plurality of recording elements, including: decoding means for receiving a signal from the outside of the recording head, for outputting a larger number of signals than the number of the received signal according to the received signal, and for driving the plurality of recording elements according to the output signals; and a circuit for identifying the type of the recording head, wherein the circuit for identifying the type of the recording head is connected to any of the output signal lines of the decoding means.
One of the foregoing objects is achieved in yet another aspect of the present invention through the provision of an apparatus which can detachably mount a head and drive the head, including: a head provided with a driving signal line having a driving terminal for receiving a driving signal of the head from the apparatus and a head identification terminal electrically connected to the driving signal line; and driving-signal supplying means for sending a driving signal to the driving signal terminal.
One of the foregoing objects is achieved in still another aspect of the present invention through the provision of an apparatus which can detachably mount a recording head and drive the recording head, including: decoding means for receiving a signal from the outside of the recording head, for outputting a larger number of signals than the number of the received signal according to the received signal, and for driving a plurality of recording elements according to the output signals; the recording head connected to any of the output signal lines of the decoding means; and driving-signal supplying means for sending a driving signal to the recording head.
One of the foregoing objects is achieved in a further aspect of the present invention through the provision of a method for giving identification information to a head, including the step of: cutting at least a part of a plurality of patterns used for connecting in a head an identification terminal to a driving signal line having a driving terminal for receiving a driving signal of the head from an apparatus.
One of the foregoing objects is achieved in a still further aspect of the present invention through the provision of a head identification method for identifying a head which includes an identification terminal and a driving signal line having a driving terminal for receiving a driving signal of the head from an apparatus, wherein a signal is sent to the driving terminal of the head; and the head is identified according to the signal read from the identification terminal.
One of the foregoing objects is achieved in a yet further aspect of the present invention through the provision of a recording-head identification method for identifying a recording head, wherein decoding means is provided, for receiving a signal from the outside of the recording head, for outputting a larger number of signals than the number of the received signal according to the received signal, and for driving a plurality of recording elements according to the output signals; a signal input to the decoding means any of whose output signal lines is connected to a circuit for identifying the type of the recording head is changed; and the output signal corresponding to the input signal, obtained from the circuit for identifying the type of the recording head is detected to identify the type of the recording head.
According to the configurations described above, without providing a special circuit, such as a memory or a serial-transfer circuit for identification information, for a head, a head which allows many types of heads to be identified by the use of driving signal lines provided in advance for the head, and an apparatus having the head are provided.
In the above method for identifying a head, many heads can be easily identified by sending a drive signal through a drive signal line and monitoring the output signal of an identification terminal.
In the above method for giving identification information to a head, since identification information is given to a head in which a driving signal line and an identification terminal are connected by a plurality of patterns, just by electrically cutting a part of the plurality of patterns, identification information can be easily given at a low cost.
According to each configuration and method described above, since a signal sent to a head and decoded is used to identify the type of the head, many heads are easily identified without a large change in circuit.
In addition, since a plurality of recording elements, decoding means, and a circuit for identifying the type of a head are mounted on the same element substrate, even a head which allows a plurality of heads to be identified can be made very compact at a low cost.
As described above, according to the present invention, a very large number of units can be identified without providing extra contacts for identification. As a result, a number of optional products can be implemented without reducing reliability and without making an apparatus to a large scale at a low cost.
According to the present invention, with a driving signal line being electrically connected to an identification terminal, a number of heads can be identified with a low number of terminals.
Head identification information can be given to a head just by cutting a pattern connecting a driving signal line to an identification terminal, and a low-cost head can be manufactured in a simple manufacturing process.